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Windows 7: Within Windows 7, CHKDSK detects C: drive as raw (unrecognized)

22 Mar 2015   #1

Windows 7 Pro 64-bit
Within Windows 7, CHKDSK detects C: drive as raw (unrecognized)

Would appreciate any advice on this problem, it has me stumped. I have a machine that ran XP Pro 32-bit flawlessly for several years. I upgraded to Windows 7 Pro 64-bit, by wiping the system drive and doing a clean install. Setup created a system reserved partition (c: ) and the Win7 install partition (g: as the machine has several drives with multiple partitions). If I boot to the recovery environment, chkdsk sees these drive letters and does not detect any errors on them.

The machine will boot normally into Windows 7, and it does the required substitution so that the system reserved partition has no drive letter, and the Win7 install partition becomes c:. But if I run chkdsk c: from an elevated command prompt, it reports that drive c: is a raw partition (unrecognized). Yet the machine is running with c: as the Win7 install disk, and I can access it without problems. The issues that occur are as follows:

1. chkdsk c: from within Win7 reports the partition as raw, but this takes a long time and the computer becomes unresponsive while chkdsk runs, returning to normal after chkdsk reports raw status.

2. the disk management console takes a very long time to load the disk information, but does eventually report it correctly, showing c: as the Win7 install drive, as well as the system reserved partition with no drive letter. All volumes are reported as healthy.

3. if I boot to safe mode, chkdsk c: does correctly detect the Win7 install drive and reports NTFS, also no problems on that drive.

4. if I try to do an in-place upgrade of Win 7 (as a repair install), the machine becomes slower and slower and eventually does a BSOD with error code 7a.

5. about twice a month, the machine running normally under Win7 will reboot after a BSOD error code 7a. This seems to happen after instances of extensive system disk use (Windows updates, etc).

So I'm guessing this is either a driver issue or an incorrect registry entry. The only unusual thing about this machine is it uses an Adaptec 29320 SCSI controller and Seagate SCSI hard disks. I've checked out the controller diagnostics and it reports both the controller and disks as ok.

Any thoughts?

My System SpecsSystem Spec
22 Mar 2015   #2

Microsoft Community Contributor Award Recipient

Windows 7 Home Premium SP1, 64-bit

Post a screen shot of Windows Disk Management so we can better visualize the problem.

You say "Setup created a system reserved partition (c: )". Any idea why that happened?

I'd expect it to have no drive letter by default.
My System SpecsSystem Spec
22 Mar 2015   #3

Windows 7 Pro 64-bit

The drive letter assignment was done by Windows Setup. My understanding is that it's normal for the system reserved partition to have a drive letter for the recovery environment, but that Windows on boot (and by default) switches the drive letters to be consistent with c: being the boot volume, and shows the system reserved partition with no drive letter. At least that is the case for my machine. The question is why chkdsk doesn't see this from inside Windows, but the system works anyway?

Attached Thumbnails
Within Windows 7, CHKDSK detects C: drive as raw (unrecognized)-disk_man.png  
My System SpecsSystem Spec

22 Mar 2015   #4
Microsoft MVP


It certainly sounds like a failing drive. Run the maker's HD Diagnostic extended CD scan to know for sure.

Then if necessary replace the drive to run a Clean Reinstall Windows 7.

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My System SpecsSystem Spec
22 Mar 2015   #5

Windows 7 Pro 64-bit

As mentioned, the drive checks out as ok. It passes chkdsk and drive utilities outside of Windows 7 or in Windows 7 safe mode. So most likely something in the Windows 7 normal boot configuration is interfering with chkdsk's ability to read the drive, as well as causing periodic BSOD's. Just not sure what it is.

Chkdsk is a black box and there are no real alternatives. I tried TestDisk but it also reports the drive and all partitions as ok, even from within Windows. It does not return the raw type for any partition. Also Seagate utilities reports the drive tests successfully, both inside and outside of Windows 7.

Guess I'll keep looking. Thanks everyone, for the help.
My System SpecsSystem Spec
22 Mar 2015   #6

Linux Lite 3.2 x64; Windows 7, 8.1

3. if I boot to safe mode, chkdsk c: does correctly detect the Win7 install drive and reports NTFS, also no problems on that drive.
This seems to be the key to the problem. I would do a clean "diagnostics" boot via MSCONFIG and see what that does. If it works, start adding things back until you can isolate the problem. Check Task Scheduler while you're at it. Autoruns is good for this, but has to be used with caution (use Restore Points). CCleaner does a good job too.

Another possibility is ghosted devices. This can come into play particularly when hardware has been changed or when the install is a clone of a different machine. GhostBuster is a great tool for finding and uninstalling ghosted devices that might be causing conflicts.
My System SpecsSystem Spec
22 Mar 2015   #7

W7 Ultimate SP1, LM19.2 MATE, W10 Home 1703, W10 Pro 1703 VM, #All 64 bit
Power & Data Connections

Make sure that the power and data connections are properly seated on the HDD and motherboard.
Also if possible try using different SATA cables.

A couple of weeks ago I experienced something a weird issue with an external HDD.
I ran Check Disk and it reported no issues.
Less than a minute later, the drive vanished from Windows Explorer and Windows asked if I wanted to format it.
The HDD had some weird adapter (SATA to USB 3) which somehow became faulty and caused the issue.

I'm now using the HDD internally (i.e. connected to my motherboard).
My System SpecsSystem Spec
22 Mar 2015   #8
Microsoft MVP


I'm sorry but I don't see where you "mention" that you'd done the actual hard drive maker's bootable diagnostics which is the only way to know for certain the drive's condition since it check's the physical surface, while Disk Check only checks the file system that resides upon it?

The drive is only tested good if it passes both tests, or if there are errors it fixes them enough that the drive passes a second test. But most of us would not trust the drive enough after that to keep using it.
My System SpecsSystem Spec
22 Mar 2015   #9

Windows 7 Pro 64-bit

Thanks everyone, for the suggestions. Starting up clean with drivers added until failure is a good idea. The machine is installed at a co-location site, but I'll try that next time I can get access. I was hoping for something I could try remotely but I can schedule another access session.

As far as the disk, it's been tested by the SCSI controller verify utility, which checks the disk surface. It's also been tested by chkdsk /r and /x, and by the Seagate disk utilities which also test the surface. Finally it's been tested by TestDisk. All the tests come up good, no errors or problems on the disk. It has been marked dirty a few times due to the BSOD, but that's expected.

I really think the controller and disk are ok. But a loose SCSI connection is also possible, I'd have to pull the machine from the rack to check that. Maybe I can do that at the next access session.
My System SpecsSystem Spec
27 Mar 2015   #10

Windows 7 Pro 64-bit

FYI, I did some testing and found that Windows Superfetch contributes to the problem. Superfetch does not run in safe mode, and when in Windows with the Superfetch service disabled, I can run chkdsk c: from within Windows and the computer responds normally. Couldn't do that before.

So possibly there is an incompatibility between Superfetch and the SCSI disk drivers, or Superfetch increases the disk load to the point of driver instability. I noticed that Superfetch disk accesses sometimes were taking several seconds and numerous requests from Superfetch were queued. Other disk processes had normal access times. Not sure why Superfetch would be different.
My System SpecsSystem Spec

 Within Windows 7, CHKDSK detects C: drive as raw (unrecognized)

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